Conventional air-conditioners are effective in removing Sensible Heat (SH) and less effective in removing Latent Heat (LH). To remove heat, the evaporator of the air-conditioner must be cold compared with the ambient air which is normally about 26.degree. C. Yet to remove vapor, the evaporator should be cold compared with the dew point temperature, which is about 15.degree. C.
It can be shown that when the LH exceeds the SH, the humidity in a conventionally conditioned enclosed space exceeds 60%, which humidity is the maximum humidity recommended for maintaining a comfortable environment. For this reason, in humid climate air-conditioning systems require an absorption machine which, while removing humidity, heats the enclosed space, and thus, reduces the efficiency of the conditioning system.
In PCT Application Publication No. WO96/33378, there is disclosed a heat pump system and method for air-conditioning utilizing a refrigerant evaporation and a refrigerant condenser for exchanging heat with brine solution. The refrigerant is considered to have an adverse effect on the ozone, and thus, it is recommended to avoid the use thereof.